The present invention relates generally to an intraluminal graft having an integral structural support which supports the intraluminal graft in an open condition and a method for making the inventive intraluminal graft. The integral structural support enhances dimensional stability of the graft, provides radial strength against radial constriction or collapse, yet permits radial expansion of the graft and facilitates intraluminal anchoring of the graft into the tissue defining an anatomical passageway. The integrally structurally supported endoluminal graft of the present invention includes a structural support integrally coupled to the graft and which has a plurality of strain relief segments. The strain relief segments, upon cumulative longitudinal deformation, delimit an upper limit of longitudinal and/or radial expansion of the graft itself.
The current trend is toward minimally invasive surgical procedures. Laparoscopic, endoscopic and percutaneous catheterization procedures have permitted surgeons to treat a broad spectrum of diseases and disorders while reducing body trauma, using local anesthesia, and decreasing patient pain and recovery time. Endovascular procedures such as percutaneous transluminal angioplasty (PTA) to treat vascular occlusive diseases, abdominal aortic aneurysm exclusions or peripheral aneurysmal exclusions are examples of minimally invasive interventional cardiovascular applications which have gained popularity. The present invention may be used with other endoscopic or percutaneous catheterization procedures for treating occlusive disorders in other anatomical passageways, including, but not limited to biliary ducts, ureters, urethras, fallopian tubes, etc. or to create shunts to restore blood flow, such as a transjugular intrahepatic portosystemic shunt (TIPS).
The present invention relates to various embodiments of an intraluminal graft, preferably made from longitudinally expanded polytetrafluoroethylene (ePTFE), which incorporate a structural member within or adjacent to the graft wall. In accordance with the preferred embodiment of the invention, a wire or ribbon member, fabricated of either metal or plastic, is incorporated either directly into the wall of the graft or into beading bonded to the graft. The structural member includes strain relief sections which permit both radial and longitudinal expansion of the graft. The structural member may further include tissue anchors comprising barbs or barb-forming sections distinct from the strain relief sections, or the strain relief sections may, themselves, act as the tissue anchors to anchor the graft to the anatomical passageway tissue.
The object of the present invention is to provide an structurally supported intraluminal graft useful as an endovascular graft which can be radially expanded in vivo, similar to endovascular stents described in U.S. Pat. No. 4,733,665 issued to Palmaz and U.S. Pat. No. 4,580,568 issued to Gianturco, which are well known in the art and which are currently being employed in many endovascular applications. The purpose of the present invention is to provide means which function to provide radial reinforcement for the graft, permitting radial expansion thereof, and which permits affixing the graft within an anatomical passageway such as a blood vessel.
Several strengthened or reinforced, yet radially compliant graft structures have been described in the art. For example, the Pinchuk patent, U.S. Pat. No. 4,629,458, discloses a tubular graft with an internal support layer. A silicone mandrel is coated with a fluid polymer and then helically wrapped with a monofilament polymer. The helical wrap may, alternatively, be positioned within the wall of the graft.
The Wall patent, U.S. Pat. No. 5,192,307 describes a radially expandable compliant prosthesis having metal springs embedded into the wall of the prosthesis. The prosthesis comprises a stent including a wall with a hook and hook means. The stent comprises a network of stainless steel or woven plastic covered by a plastic material. A plurality of circumferential ribs are placed about the stent to engage the arterial walls and prevent the inadvertent movement of the stent.
The Schwartz et al. patent, U.S. Pat. No. 5,282,823, describes a stent comprising a cylindrical body having a plurality of substantially helical metal elements joined together with a polymeric film extending between adjacent helical metal elements. The polymeric film has strain relief sections consisting of slits or cuts in the film between adjacent helical elements. The helical elements allow flexing of the stent along its longitudinal axis.
The Palmaz patent, U.S. Pat. No. 4,776,337, describes an expandable intraluminal composite graft comprising a tubular shaped member, comprising intersecting elongate members, and a biological inert coating placed over the tubular shaped member.
The Tessmann et al. patent, U.S. Pat. No. 5,167,614, describes a prostatic stent comprising a coiled rigid sheet, which may be expanded, and a plurality of hook like projections on the outer wall of the coil for anchoring the stent to the wall of a body passage. However, a grasping tool is required to expand and anchor the stent.
Other grafts attempt to replicate the inherent compliance of blood vessels. For example, the Kira patent, U.S. Pat. No. 4,857,069 discloses a composite artificial vessel having compliance and stress strain curves which approximate those of an actual blood vessel. The artificial vessel is made by coating a mandrel with an elastomer solution having a pore-forming agent and/or an elastomer solution having a cloud point, and immersing the coated mandrel into a coagulating liquid. The resulting artificial vessel has a porosity and compliance similar to a blood vessel.